Method and apparatus for transmitting wireless local area network data

ABSTRACT

A method comprises constructing, by an access point (AP), a radio frame within a scheduling window, the radio frame including at least a preamble part compatible with an existing IEEE 802.11 preamble legacy preamble, a preamble part used in a next-generation IEEE 802.11 standard (HEW preamble), and the first downlink subframe (DL subframe); sending the Legacy preamble, the HEW preamble and the first DL subframe in the radio frame; receiving at least one uplink subframe (UL subframe) located after the first DL subframe; wherein each of the at least one UL subframes is triggered by one DL subframe located before the UL subframe.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/837,827, filed on Apr. 1, 2020, which is a continuation of U.S.patent application Ser. No. 16/384,522, filed on Apr. 15, 2019, now U.S.Pat. No. 10,631,322, which is a continuation of U.S. patent applicationSer. No. 15/249,795, filed on Aug. 29, 2016, now U.S. Pat. No.10,264,599, which is a continuation of International Application No.PCT/CN2014/093869, filed on Dec. 15, 2014, which claims priority toInternational Application No. PCT/CN2014/072617, filed on Feb. 27, 2014,and International Application No. PCT/CN2014/092960, filed on Dec. 3,2014. All of the aforementioned patent applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to the field of communications, and inparticular, to a method and an apparatus for transmitting wireless localarea network data.

BACKGROUND

With the rapid development of communications technologies, a wirelesslocal area network (WLAN) technology based on the IEEE 802.11 standardhas been considerably developed and widely applied. A WLAN network mayinclude multiple Access Points (APs) and multiple stations (STAs), whereeach AP may be associated with multiple STAs, and each AP may transmit,using a radio channel, wireless local area network data with a STA thatis associated with the AP.

A current method for transmitting wireless local area network dataincludes, when the AP sends wireless local area network data to a STAassociated with the AP, the AP listens on a radio channel. When theradio channel is not occupied over a period of time, the AP accesses theradio channel and acquires a right to use the radio channel. The APencapsulates wireless local area network data that needs to betransmitted into a PLCP protocol data unit (PPDU), and sends the PPDU tothe STA. When a STA associated with the AP sends wireless local areanetwork data to the AP, the STA listens on the radio channel. When theradio channel is not occupied over a period of time, the STA accessesthe radio channel and acquires the right to use the radio channel. TheSTA encapsulates wireless local area network data that needs to betransmitted into a PPDU and sends the PPDU to the AP.

As shown in FIG. 1 and FIG. 2 , the first row of FIG. 1 shows aconventional PPDU frame format, and the second row and the third row ofFIG. 1 show a PPDU frame format according to 802.11n. FIG. 2 shows aPPDU frame format according to 802.11ac. A STA may encapsulate, by usingthe frame format of FIG. 1 or FIG. 2 , wireless local area network datainto a PPDU and send the PPDU to an AP. Accordingly, an AP mayencapsulate, by using the PPDU frame format of FIG. 1 or FIG. 2 ,wireless local area network data into a PPDU and send the PPDU to a STA.L-STF, HT-STF, and HT-GF-STF are short training fields, L-LTF, HT-LTF1,HT-LTF, and VHT-LTF are long training fields, L-SIG, HT-SIG, VHT-SIG-A,and VHT-SIG-B are signaling fields, and Data is a data field.

A WLAN network uses a free unauthorized frequency band, and uses acontention-based access mechanism to acquire a right to use a radiochannel. When a STA/AP acquires the right to use the radio channel,wireless local area network data is transmitted between the AP and theSTA in a one-to-one relationship. However, the wireless local areanetwork data cannot be transmitted between the AP and the STA in aone-to-many relationship, or between the STA and the AP in a many-to-onerelationship, which reduces spectrum utilization and network useefficiency.

SUMMARY

To improve spectrum utilization and network use efficiency, embodimentsherein provide a method and an apparatus for transmitting wireless localarea network data. The technical solutions are as follows:

According to a first aspect, An apparatus for transmitting wirelesslocal area network data, wherein the apparatus comprises non-transitoryreadable storage medium, which includes several instructions forinstructing a processor to perform the following methods:

constructing a radio frame within a scheduling window, the radio frameat least includes a preamble part compatible with the existing IEEE802.11 (Legacy preamble), a preamble part used in a next-generation IEEE802.11 standard (HEW preamble), and the first downlink subframe (DLsubframe); sending the Legacy preamble, the HEW preamble and the firstDL subframe in the radio frame; receiving at least one uplink subframe(UL subframe) located after the first DL subframe within the schedulingwindow; wherein each of the at least one UL subframes is triggered byone DL subframe located before the UL subframe.

An apparatus for transmitting wireless local area network data, whereinthe apparatus comprises non-transitory readable storage medium, whichincludes several instructions for instructing a processor to perform thefollowing methods:

receiving a radio frame within a scheduling window, the radio frame atleast includes a preamble part compatible with the existing IEEE 802.11,Legacy preamble, a preamble part used in a next-generation IEEE 802.11standard, HEW preamble, and the first downlink subframe, DL subframe;sending at least one uplink subframe, UL subframe, located after thefirst DL subframe; wherein each of the at least one UL subframes istriggered by one DL subframe located before the UL subframe.

An method for transmitting wireless local area network data, wherein themethod comprises:

constructing a radio frame within a scheduling window, the radio frameat least includes a preamble part compatible with the existing IEEE802.11 (Legacy preamble), a preamble part used in a next-generation IEEE802.11 standard (HEW preamble), and the first downlink subframe (DLsubframe);

sending the Legacy preamble, the HEW preamble and the first DL subframein the radio frame;

receiving at least one uplink subframe (UL subframe) located after thefirst DL subframe within the scheduling window; wherein each of the atleast one UL subframes is triggered by one DL subframe located beforethe UL subframe.

In the embodiments herein, when a right to use a radio channel isacquired, an AP may construct a radio frame, and send, in a downlinkdata domain of the radio frame, wireless local area network data to aSTA associated with the AP. In this way, the AP may send the wirelesslocal area network data to the STA associated with the AP, improvingspectrum utilization and network use efficiency.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in the embodiments herein, thefollowing briefly introduces the accompanying drawings required fordescribing the embodiments. The accompanying drawings in the followingdescription show merely some embodiments, and a person of ordinary skillin the art may still derive other drawings from these accompanyingdrawings without creative efforts.

FIG. 1 is a schematic diagram of a PPDU frame format provided in theprior art;

FIG. 2 is a schematic diagram of another PPDU frame format provided inthe prior art;

FIG. 3 is a schematic structural diagram of an apparatus fortransmitting wireless local area network data according to anembodiment;

FIG. 4 is a schematic structural diagram of an apparatus fortransmitting wireless local area network data according to anembodiment;

FIG. 5 is a flowchart of a method for transmitting wireless local areanetwork data according to an embodiment;

FIG. 6 is a flowchart of a method for transmitting wireless local areanetwork data according to an embodiment;

FIG. 7 is a flowchart of a method for transmitting wireless local areanetwork data according to an embodiment;

FIG. 8 is a schematic diagram of a frame format of a radio frameaccording to an embodiment;

FIG. 8A-8C respectively is a schematic diagram of a frame format of aradio frame according to an embodiment;

FIG. 9 is a schematic diagram of a preamble part of a radio frameaccording to an embodiment;

FIG. 10 is a schematic structural diagram of an apparatus fortransmitting wireless local area network data according to anembodiment;

FIG. 11 is a schematic structural diagram of an apparatus fortransmitting wireless local area network data according to anembodiment; and

FIG. 12 is a schematic diagram of a frame format of a radio frameaccording to an embodiment.

DESCRIPTION OF EMBODIMENTS

To make the objectives, technical solutions, and advantages of thepresent description clearer, the following further describes theembodiments in detail, with reference to the accompanying drawings.

When a right to use a radio channel is acquired, an AP constructs aradio frame, where the radio frame includes a preamble part, a controldomain, and a data domain. The AP in some embodiments constructs theradio frame with a scheduling window. The data domain may include atleast one downlink data domain, and the downlink data domain includesmultiple radio resource blocks, where each STA associated with the APhas a corresponding radio resource block. The AP may transmit, on aradio resource block corresponding to each STA in the downlink datadomain, wireless local area network data to a STA associated with theAP, improving spectrum utilization and network use efficiency.

With reference to multiple embodiments, the following describessolutions and effects in more detail by using a next-generation wirelesslocal area network (WLAN) as an example. In the following embodiments, aquantity of STAs associated with the AP may be one, or may be multiple.

Embodiment 1

FIG. 3 is an apparatus for transmitting wireless local area network dataaccording to an embodiment. Referring to FIG. 3 , the apparatusincludes:

a constructing module 301, configured to construct a radio frame when aright to use a radio channel is acquired, where the radio frame includesat least a preamble part, a control domain, and a data domain, and thedata domain includes at least one downlink data domain;

a first sending module 302, configured to send the preamble part and thecontrol domain to a station STA associated with an access point AP; and

a second sending module 303, configured to send, in a downlink datadomain of the radio frame, wireless local area network data to the STAassociated with the AP.

A preamble of the radio frame may include a preamble part according toan IEEE 802.11 legacy preamble. The preamble may include a preamble partaccording to a next-generation IEEE 802.11 high efficiency WLAN/WiFi™(HEW) preamble. Alternatively, the preamble may include both an IEEE802.11 legacy preamble and a next-generation IEEE 802.11 HEW preamble.

Both the preamble part and the control domain are sent in an orthogonalfrequency division multiplexing OFDM manner compatible with the existingInstitute of Electrical and Electronics Engineers IEEE 802.11 standard,and the data domain is sent in an orthogonal frequency division multipleaccess OFDMA manner.

The preamble part is a preamble part compatible with the existing IEEE802.11, and the preamble part includes a legacy-short training fieldL-STF, a legacy-long training field L-LTF, and a legacy-signaling fieldL-SIG, where the L-STF is used to synchronize the STA associated withthe AP with the AP, and the L-LTF is used to enable the STA associatedwith the AP to perform channel estimation, to acquire, by means ofcoherent reception, information that is related to duration of the radioframe and carried in the L-SIG.

Further, a length LENGTH data domain in the L-SIG domain carries a valuerelated to the duration of the radio frame, and the duration,corresponding to the value, of the radio frame is greater than or equalto actual duration of the radio frame.

Optionally, the apparatus further includes:

an increasing module, configured to increase transmit power of thepreamble part of the radio frame, so that a STA not associated with theAP and another AP receive the preamble part of the radio frame, andwithin reserved duration, the STA not associated with the AP and theanother AP no longer transmit wireless local area network data by usingthe radio channel, where the reserved duration is duration within whichthe AP owns the right to use the radio channel.

Further, the control domain includes: configuration information of anuplink/downlink data domain in the radio frame, an OFDMA modulationparameter used by the data domain, and radio resource allocationindication information for the STA associated with the AP.

The configuration information of the uplink/downlink data domainincludes: a quantity of uplink data domains, a quantity of downlink datadomains, and transformation information between the uplink data domainand the downlink data domain.

Optionally, the OFDMA modulation parameter used by the data domainincludes: channel bandwidth of a system, a used cyclic prefix CP length,a fast Fourier transformation FFT order, and a quantity of availablesubcarriers.

The radio resource allocation indication information for the STAassociated with the AP includes: a first radio resource indication,where the first radio resource indication is used to indicate a radioresource block corresponding to a second radio resource indication usedby each scheduled STA to transmit data, or the first radio resourceindication is used to indicate a radio resource block used by eachscheduled STA to transmit data.

The first radio resource indication includes: a size and a position of aradio resource block indicated by the first radio resource indication,and a modulation and coding scheme and/or a multiple-inputmultiple-output MIMO transmission manner used on the radio resourceblock.

Further, the apparatus further includes:

a first receiving module, configured to: when the data domain includesan uplink data domain, receive, in the uplink data domain included inthe data domain, according to the control domain, wireless local areanetwork data sent by the STA associated with the AP.

In this embodiment, when a right to use a radio channel is acquired, anAP may construct a radio frame, where a data domain of the radio framemay include at least one downlink data domain, the downlink data domainincludes multiple radio resource blocks, and each STA has acorresponding radio resource block. The AP may send, on a radio resourceblock corresponding to a STA in the downlink data domain, wireless localarea network data to a STA associated with the AP. When the data domainof the radio frame includes an uplink data domain, the uplink datadomain also includes multiple radio resource blocks, and each STA has acorresponding radio resource block. The STA associated with the AP maysend, on a radio resource block corresponding to the STA, wireless localarea network data to the AP. Because the AP may be associated withmultiple STAs, the wireless local area network data can be transmittedbetween the AP and the STA in a one-to-many or many-to-one relationship,improving spectrum utilization and network use efficiency.

Embodiment 2

FIG. 4 is an apparatus for transmitting wireless local area network dataaccording to an embodiment. Referring to FIG. 4 , the apparatusincludes:

a second receiving module 401, configured to receive a preamble part anda control domain of a radio frame that are sent by an access point APassociated with a STA; and

a third receiving module 402, configured to receive, in a downlink datadomain included in a data domain of the radio frame, according to thepreamble part and the control domain, wireless local area network datasent by the AP associated with the STA, where the data domain includesat least one downlink data domain.

The preamble part is a preamble part compatible with the existingInstitute of Electrical and Electronics Engineers IEEE 802.11, and thepreamble part includes a legacy-short training field L-STF, alegacy-long training field L-LTF, and a legacy-signaling field L-SIG;and

accordingly, the apparatus further includes:

a synchronization module, configured to perform, according to the L-STF,synchronization with the AP associated with the STA;

a channel estimation module, configured to perform channel estimationaccording to the L-LTF; and

an acquiring module, configured to acquire, by means of coherentreception, information that is related to duration of the radio frameand carried in the L-SIG.

Further, a length LENGTH data domain in the L-SIG domain carries a valuerelated to the duration of the radio frame, and the duration,corresponding to the value, of the radio frame is greater than or equalto actual duration of the radio frame.

The control domain includes: configuration information of anuplink/downlink data domain in the radio frame, an OFDMA modulationparameter used by the data domain, and radio resource allocationindication information for the STA associated with the AP.

The configuration information of the uplink/downlink data domainincludes: a quantity of uplink data domains, a quantity of downlink datadomains, and transformation information between the uplink data domainand the downlink data domain.

Optionally, the OFDMA modulation parameter used by the data domainincludes: channel bandwidth of a system, a used cyclic prefix CP length,a fast Fourier transformation FFT order, and a quantity of availablesubcarriers.

The radio resource allocation indication information for the STAassociated with the AP includes: a first radio resource indication,where the first radio resource indication is used to indicate a radioresource block corresponding to a second radio resource indication usedby each scheduled STA to transmit data, or the first radio resourceindication is used to indicate a radio resource block used by eachscheduled STA to transmit data.

The first radio resource indication includes: a size and a position of aradio resource block indicated by the first radio resource indication,and a modulation and coding scheme and/or a multiple-inputmultiple-output MIMO transmission manner used on the radio resourceblock.

Further, the apparatus further includes:

a third sending module, configured to: when the data domain includes anuplink data domain, send, in the uplink data domain included in the datadomain, according to the control domain, wireless local area networkdata to the AP associated with the STA.

In this embodiment, when a right to use a radio channel is acquired, anAP may construct a radio frame, where a data domain of the radio framemay include at least one downlink data domain, the downlink data domainincludes multiple radio resource blocks, and each STA has acorresponding radio resource block. The AP may send, on a radio resourceblock corresponding to a STA in the downlink data domain, wireless localarea network data to a STA associated with the AP. When the data domainof the radio frame includes an uplink data domain, the uplink datadomain also includes multiple radio resource blocks, and each STA has acorresponding radio resource block. The STA associated with the AP maysend, on a radio resource block corresponding to the STA, wireless localarea network data to the AP. Because the AP may be associated withmultiple STAs, the wireless local area network data can be transmittedbetween the AP and the STA in a one-to-many or many-to-one relationship,improving spectrum utilization and network use efficiency.

Embodiment 3

FIG. 5 is a method for transmitting wireless local area network dataaccording to an embodiment. Referring to FIG. 5 , the method includes:

Step 501: When a right to use a radio channel is acquired, an accesspoint AP constructs a radio frame, where the radio frame includes atleast a preamble part, a control domain, and a data domain, and the datadomain includes at least one downlink data domain.

Step 502: The AP sends the preamble part and the control domain to astation STA associated with the AP.

Step 503: The AP sends, in a downlink data domain of the radio frame,wireless local area network data to the STA associated with the AP.

Both the preamble part and the control domain are sent in an orthogonalfrequency division multiplexing OFDM manner compatible with the existingInstitute of Electrical and Electronics Engineers IEEE 802.11 standard,and the data domain is sent in an orthogonal frequency division multipleaccess OFDMA manner.

The preamble part is a preamble part compatible with the existing IEEE802.11, and the preamble part includes a legacy-short training fieldL-STF, a legacy-long training field L-LTF, and a legacy-signaling fieldL-SIG, where the L-STF is used to synchronize the STA associated withthe AP with the AP, and the L-LTF is used to enable the STA associatedwith the AP to perform channel estimation, to acquire, by means ofcoherent reception, information that is related to duration of the radioframe and carried in the L-SIG.

Further, a length LENGTH data domain in the L-SIG domain carries a valuerelated to the duration of the radio frame, and the duration,corresponding to the value, of the radio frame is greater than or equalto actual duration of the radio frame.

Optionally, the method further includes:

increasing, by the AP, transmit power of the preamble part of the radioframe, so that a STA not associated with the AP and another AP receivethe preamble part of the radio frame, and within reserved duration, theSTA not associated with the AP and the another AP no longer transmitwireless local area network data by using the radio channel, where thereserved duration is duration within which the AP owns the right to usethe radio channel.

The control domain includes: configuration information of anuplink/downlink data domain in the radio frame, an OFDMA modulationparameter used by the data domain, and radio resource allocationindication information for the STA associated with the AP.

The configuration information of the uplink/downlink data domainincludes: a quantity of uplink data domains, a quantity of downlink datadomains, and transformation information between the uplink data domainand the downlink data domain.

Further, the OFDMA modulation parameter used by the data domainincludes: channel bandwidth of a system, a used cyclic prefix CP length,a fast Fourier transformation FFT order, and a quantity of availablesubcarriers.

The radio resource allocation indication information for the STAassociated with the AP includes: a first radio resource indication,where the first radio resource indication is used to indicate a radioresource block corresponding to a second radio resource indication usedby each scheduled STA to transmit data, or the first radio resourceindication is used to indicate a radio resource block used by eachscheduled STA to transmit data.

The first radio resource indication includes: a size and a position of aradio resource block indicated by the first radio resource indication,and a modulation and coding scheme and/or a multiple-inputmultiple-output MIMO transmission manner used on the radio resourceblock.

Optionally, the method further includes:

when the data domain includes an uplink data domain, receiving, by theAP, in the uplink data domain included in the data domain, according tothe control domain, wireless local area network data sent by the STAassociated with the AP.

In this embodiment, when a right to use a radio channel is acquired, anAP may construct a radio frame, where a data domain of the radio framemay include at least one downlink data domain, the downlink data domainincludes multiple radio resource blocks, and each STA has acorresponding radio resource block. The AP may send, on a radio resourceblock corresponding to a STA in the downlink data domain, wireless localarea network data to a STA associated with the AP. When the data domainof the radio frame includes an uplink data domain, the uplink datadomain also includes multiple radio resource blocks, and each STA has acorresponding radio resource block. The STA associated with the AP maysend, on a radio resource block corresponding to the STA, wireless localarea network data to the AP. Because the AP may be associated withmultiple STAs, the wireless local area network data can be transmittedbetween the AP and the STA in a one-to-many or many-to-one relationship,improving spectrum utilization and network use efficiency.

Embodiment 4

FIG. 6 is a method for transmitting wireless local area network dataaccording to an embodiment. Referring to FIG. 6 , the method includes:

Step 601: A station STA receives a preamble part and a control domain ofa radio frame that are sent by an access point AP associated with theSTA.

Step 602: The STA receives, in a downlink data domain included in a datadomain of the radio frame, according to the preamble part and thecontrol domain, wireless local area network data sent by the APassociated with the STA, where the data domain includes at least onedownlink data domain.

The preamble part is a preamble part compatible with the existingInstitute of Electrical and Electronics Engineers IEEE 802.11, and thepreamble part includes a legacy-short training field L-STF, alegacy-long training field L-LTF, and a legacy-signaling field L-SIG;and accordingly, after the receiving, by a station STA, a preamble partand a control domain of a radio frame that are sent by an access pointAP associated with the STA, the method further includes:

performing, by the STA according to the L-STF, synchronization with theAP associated with the STA;

performing, by the STA, channel estimation according to the L-LTF; and

acquiring, by the STA by means of coherent reception, information thatis related to duration of the radio frame and carried in the L-SIG.

A length LENGTH data domain in the L-SIG domain carries a value relatedto the duration of the radio frame, and the duration, corresponding tothe value, of the radio frame is greater than or equal to actualduration of the radio frame.

Further, the control domain includes: configuration information of anuplink/downlink data domain in the radio frame, an OFDMA modulationparameter used by the data domain, and radio resource allocationindication information for the STA associated with the AP.

The configuration information of the uplink/downlink data domainincludes: a quantity of uplink data domains, a quantity of downlink datadomains, and transformation information between the uplink data domainand the downlink data domain.

Further, the OFDMA modulation parameter used by the data domainincludes: channel bandwidth of a system, a used cyclic prefix CP length,a fast Fourier transformation FFT order, and a quantity of availablesubcarriers.

The radio resource allocation indication information for the STAassociated with the AP includes: a first radio resource indication,where the first radio resource indication is used to indicate a radioresource block corresponding to a second radio resource indication usedby each scheduled STA to transmit data, or the first radio resourceindication is used to indicate a radio resource block used by eachscheduled STA to transmit data.

The first radio resource indication includes: a size and a position of aradio resource block indicated by the first radio resource indication,and a modulation and coding scheme and/or a multiple-inputmultiple-output MIMO transmission manner used on the radio resourceblock.

Optionally, the method further includes:

when the data domain includes an uplink data domain, sending, by theSTA, in the uplink data domain included in the data domain, according tothe control domain, wireless local area network data to the APassociated with the STA.

In this embodiment, when a right to use a radio channel is acquired, anAP may construct a radio frame, where a data domain of the radio framemay include at least one downlink data domain, the downlink data domainincludes multiple radio resource blocks, and each STA has acorresponding radio resource block. The AP may send, on a radio resourceblock corresponding to a STA in the downlink data domain, wireless localarea network data to a STA associated with the AP. When the data domainof the radio frame includes an uplink data domain, the uplink datadomain also includes multiple radio resource blocks, and each STA has acorresponding radio resource block. The STA associated with the AP maysend, on a radio resource block corresponding to the STA, wireless localarea network data to the AP. Because the AP may be associated withmultiple STAs, the wireless local area network data can be transmittedbetween the AP and the STA in a one-to-many or many-to-one relationship,improving spectrum utilization and network use efficiency.

Embodiment 5

FIG. 7 is a method for transmitting wireless local area network dataaccording to an embodiment. Referring to FIG. 7 , the method includes:

Step 701: When a right to use a radio channel is acquired, an APconstructs a radio frame, where the radio frame includes at least apreamble part, a control domain, and a data domain, and the data domainincludes at least one downlink data domain.

A specific operation of acquiring a right to use a radio channel may be:listening on the radio channel, and detecting energy of the radiochannel. When it is detected that the energy of the radio channel isless than a preset threshold, and it is detected that n NAV (networkallocation vector) is not set, it is determined that the radio channelis not occupied at a current moment. After a random backoff time, if theradio channel is still not occupied, access is made to the radiochannel, to acquire the right to use the radio channel.

Both the AP and a STA associated with the AP may acquire the right touse the radio channel. After the STA associated with the AP acquires theright to use the radio channel, the STA associated with the AP sends anotification message to the AP to notify the AP.

Further, when the right to use the radio channel is acquired, the AP mayfurther construct a reserved control frame according to an address ofthe AP and reserved duration, where the reserved duration is durationduring which the AP owns the right to use the radio channel. The APbroadcasts the reserved control frame, to state that the AP and the STAassociated with the AP use the radio channel within nearest reservedduration after a current time.

The AP broadcasts the reserved control frame, so that after receivingthe reserved control frame, a STA not associated with the AP and anotherAP may no longer acquire the right to use the radio channel within thenearest reserved duration after the current time, avoiding impact causedon the AP and the STA associated with the AP by the STA not associatedwith the AP and the another AP.

It should be noted that the reserved duration may be preset, or may beconfigured by the AP, which is not specifically limited in thisembodiment.

Optionally, when the right to use the radio channel is acquired, the APmay further group the reserved duration as at least one radio frame. Inthe at least one radio frame obtained by means of grouping, duration ofeach radio frame and duration of a SIFS (short inter-frame space) arepre-configured. The duration of the SIFS is a time interval between twoneighboring radio frames. When a radio frame ends, the AP continues tolisten to the duration of the SIFS of the radio channel, and if theradio channel is not occupied within the duration of the SIFS, the APconstructs a next radio frame.

As shown in FIG. 8 , the AP and the STA associated with the AP mayacquire the right to use the radio channel in a contention window in aCSMA/CA (carrier sense multiple access/collision avoidance) manner. Whenthe right to use the radio channel is acquired, the AP may broadcast thereserved control frame in a reserved channel in FIG. 8 , to reserve theradio channel. After the AP reserves the radio channel, the AP enters ascheduling window, where a time length of the scheduling window isreserved duration. The AP may group the reserved duration as at leastone radio frame.

In this embodiment, not only the AP may construct the radio frameaccording to a quantity of STAs associated with the AP, but also the APmay construct the radio frame according to a service between the AP andthe STA associated with the AP. Certainly, the AP may also construct theradio frame in another manner, which is not specifically limited in thisembodiment.

The radio frame includes at least a preamble part, a control domain, anda data domain, and the data domain includes at least one downlink datadomain. When the data domain not only includes a downlink data domain,but also includes an uplink data domain, a TTG (Transmit/receiveTransition Gap) is set between the uplink data domain and the downlinkdata domain, for example, a size of the TTG may be 16 us. As shown inthe bottom half of FIG. 8 , LP is a preamble part, FC is a controldomain, DL is a downlink data domain, and UL is an uplink data domain.DL, UL, and TTG in FIG. 8 construct the data domain of the radio frame.

Further, a sum of quantities of uplink data domains and downlink datadomains in the data domain is 6 at most.

The preamble part is a preamble part compatible with the existing IEEE802.11, and the preamble part includes an L-STF (legacy-short trainingfield), an L-LTF (legacy-long training field), and an L-SIG(Legacy-Signal Field, legacy-signaling field), where the L-STF is usedto synchronize a STA associated with an AP with the AP, and the L-LTF isused to enable the STA associated with the AP to perform channelestimation, to acquire, by means of coherent reception, information thatis related to duration of the radio frame and carried in the L-SIG.

The foregoing mentioned existing IEEE 802.11 may be IEEE 802.11a, IEEE802.11g, IEEE 802.11n or IEEE 802.11ac.

A LENGTH (that is, length) data domain in the L-SIG domain carries avalue related to the duration of the radio frame, and the value isgreater than or equal to actual duration of the radio frame.

Further, the L-SIG domain further includes a rate. A time length may becalculated according to the rate and the length. The rate and the lengththat are included in the L-SIG domain may be used to configure groupinformation of a receiver.

For example, if the value is 4095, it is calculated according to therate included in the L-SIG domain that the data 4095 is corresponding to5464 us, and 5464 us is duration of the control domain and the datadomain. If the duration of the preamble part is 20 us, maximum durationof the radio frame is 5484 us.

The quantities of uplink data domains and downlink data domains in theradio frame may be configured, and duration of each uplink/downlink datadomain is pre-configured, for example, the duration of eachuplink/downlink data domain may be 896 us. If an uplink data domainexists in the radio frame, a time interval, that is, a TTG, is neededfor transformation between the downlink data domain and the uplink datadomain, where duration of the TTG may be 16 us, and the TTG may ensurethe transformation between the downlink data domain and the uplink datadomain. The duration of the control domain is 48 us or 44 us. When theduration of the control domain is 48 us, the control domain includes 12OFDM (orthogonal frequency division multiplexing) symbols, and when theduration of the control domain is 44 us, the control domain may include11 OFDM symbols, where the OFDM symbol herein is set by using an OFDMparameter of 802.11ac. It is set according to the foregoing parameterthat, when the duration of the control domain is 48 us, a maximumduration of a radio frame is 5484 us; or when the duration of thecontrol domain is 44 us, a maximum duration of a radio frame is 5480 us.

As shown in FIG. 9 , the L-SIG in the preamble part may represent apacket length by using 12 bits, which means that a maximum packet lengththat can be represented by the L-SIG field is limited to 12 bits. Alowest MCS (modulation and coding scheme) represented by a rate Ratepart is BPSK (binary phase shift keying) modulation. By using the BPSKmodulation and the packet length represented by 12 bits, maximumduration of a next packet may be calculated. A tail Tail is used toclear a channel coder, and a register of a decoder.

Further, the control domain includes: configuration information of anuplink/downlink data domain in the radio frame, an OFDMA modulationparameter used by the data domain, and radio resource allocationindication information for the STA associated with the AP.

The configuration information of the uplink/downlink data domain mayinclude: a quantity of uplink data domains, a quantity of downlink datadomains, and transformation information between the uplink data domainand the downlink data domain.

The quantities of uplink data domains and downlink data domains in theradio frame may be configured according to a service between the AP andthe STA associated with the AP. Certainly, the AP may further select aconfiguration manner from multiple pre-configured configuration mannersaccording to the service between the AP and the STA associated with theAP. For example, as shown in the following Table 1, Table 1 showsmultiple configuration manners, where D in Table 1 represents a downlinkdata domain, and U represents an uplink data domain; and Table 1 furthershows a size of a value in LENGTH included in an L-SIG corresponding toeach configuration manner. Because the duration of the control domainmay be 48 us, or may be 44 us, Table 1 shows a size of a value inLENGTH1 corresponding to 48 us, and shows a size of a value in LENGTH2corresponding to 44 us.

TABLE 1 LENGTH1 LENGTH2 48 us control 44 us control Configuration mannerdomain domain D 708 704 D U 1394 1392 D U U 2070 2067 D U U U 2745 2742D U U U U 3418 3415 D U U U U U 4094 4092 D D 1382 1378 D D U 2070 2067D D U U 2745 2742 D D U U U 3418 3415 D D U U U U 4094 4092 D D D 20562055 D D D U 2745 2742 D D D U U 3418 3415 D D D U U U 4094 4092 D D D D2733 2730 D D D D U 3418 3415 D D D D U U 4094 4092 D D D D D 3408 3405D D D D D U 4094 4092 D D D D D D 4084 4080

Further, positions of the uplink data domains and the downlink datadomains in the radio frame may also be configured.

The OFDMA modulation parameter used by the data domain may include:channel bandwidth of a system, a used CP (cyclic prefix) length, an FFT(fast Fourier transformation) order, and a quantity of availablesubcarriers.

The used CP length may also be configured according to a scenario inwhich the AP is deployed. When scenarios are quite different, channelconditions are also quite different. For example, the AP may be deployedindoors or outdoors. Different channel conditions also require differentCP lengths. Selection of a CP length is a compromise result of resourceoverheads and system performance. When an indoor channel exists betweenan AP and a STA, multipath spread is small; and in this case, using arelatively long CP may cause reduction of resource utilization. When anoutdoor channel or an outdoor to indoor channel exists between an AP anda STA, multipath spread is large; and in this case, using a relativelyshort CP may cause reduction of system performance. Therefore, a fixedCP length may fail to meet deployment of all or most of scenarios. TheAP needs to indicate, according to different deployment scenarios, touse different CP lengths. For example, in an indoor scenario, a CP of0.8 us is used; in a UMi (Urban Micro) scenario, a CP length is 4.4 us;and in a UMa (Urban Macro) scenario, a CP length is 6.4 us. The APselects a corresponding CP length according to the scenario in which theAP is deployed, and indicates the corresponding CP length in the controldomain. For example, if a system only supports indoor and UMi scenarios,1-bit information in the control domain is used for indication,indicating that 0 represents using 0.8 us, and indicating that 1represents using 4.8 us; if the system further needs to support a UMascenario, 2-bit information in the control domain needs to be used forindication, indicating that 00 represents using 0.8 us, indicating that01 represents using 4.4 us, and indicating that 02 represents using a CPof 6.4 us.

The radio resource allocation indication information for the STAassociated with the AP includes: a first radio resource indication,where the first radio resource indication is used to indicate a radioresource block corresponding to a second radio resource indication usedby each scheduled STA to transmit data, or the first radio resourceindication is used to indicate a radio resource block used by eachscheduled STA to transmit data.

The first radio resource indication includes: a size and a position of aradio resource block indicated by a first radio resource and amodulation and coding scheme and/or an MIMO (multiple-inputmultiple-output) transmission manner used on the radio resource block.

Step 702: The AP sends the preamble part and the control domain of theradio frame to a STA associated with the AP.

The preamble part and the control domain are different components of theradio frame, and the AP may first send the preamble part of the radioframe to the STA associated with the AP, and then send the controldomain of the radio frame to the STA associated with the AP.

Optionally, when the AP sends the preamble part of the radio frame tothe STA associated with the AP, the AP broadcasts the preamble part ofthe radio frame, so that not only the STA associated with the AP canreceive the preamble part of the radio frame, but also a STA notassociated with the AP can receive the preamble part of the radio frame.When the AP broadcasts the preamble part of the radio frame, the AP mayincrease transmit power of the preamble part of the radio frame, so thatthe STA not associated with the AP and another AP receive the preamblepart of the radio frame, and within reserved duration, the STA notassociated with the AP and the another AP no longer transmit wirelesslocal area network data by using the radio channel. For example, in acase in which a peak-to-average rate is met, the transmit power of thepreamble part of the radio frame may be increased by 2 dB.

By increasing the transmit power of the preamble part of the radioframe, a STA not associated with the AP and another AP may betterreceive the preamble part of the radio frame, and thereby the STA notassociated with the AP and the another AP no longer transmit wirelesslocal area network data by using the radio channel, avoidinginterference to transmission of wireless local area network data betweenthe AP and the STA associated with the AP when the STA not associatedwith the AP and the another AP transmit wireless local area networkdata, and achieving a relatively good effect.

Both the preamble part and the control domain are sent in an OFDM mannercompatible with the existing IEEE 802.11 standard.

The existing IEEE 802.11 may be IEEE 802.11a, IEEE 802.11g, IEEE 802.11nor IEEE 802.11ac.

When the preamble part and the control domain are sent, the preamblepart and the control domain may be configured and sent according to anOFDM configuration parameter. For example, as shown in Table 2, a firstvalue column in Table 2 is an OFDM configuration parameter forconfiguring the preamble part and control domain, and a second valuecolumn is an OFDMA configuration parameter of an uplink data domain anda downlink data domain.

Further, duration of each downlink data domain or uplink data domain maybe 900 us, and when a second value in Table 2 is used to perform OFDMAmodulation, each uplink or downlink data domain includes 30 OFDMsymbols.

Optionally, when the second value in Table 2 is used to perform OFDMAmodulation, each radio resource block may include 192 resource unitsoccupied by 32 subcarriers and six OFDM symbols; in this case, oneuplink or downlink data domain includes a total of 70 radio resourceblocks. Alternatively, each radio resource block may also include 160resource units occupied by 16 subcarriers and 10 OFDM symbols; in thiscase, one uplink or downlink data domain includes a total of 84 radioresource blocks.

TABLE 2 Unit First value Second value Bandwidth MHz 20 20 FFT order 64512 Subcarrier interval KHz 312.5 39.0625 OFDM symbol length us 3.2 25.6Sampling point 64 512 CP length us 0.8 4.4 Sampling point 16 80Available subcarrier 56 448

Step 703: The STA associated with the AP receives the preamble part andthe control domain of the radio frame that are sent by the AP.

The AP first sends the preamble part of the radio frame, and then sendsthe control domain of the radio frame; therefore, the STA associatedwith the AP first receives the preamble part, sent by the AP, of theradio frame, and then receives the control domain, sent by the AP, ofthe radio frame.

Step 704: The STA associated with the AP receives, in a downlink datadomain included in the data domain of the radio frame, according to thepreamble part and the control domain of the radio frame, wireless localarea network data sent by the AP.

When the STA associated with the AP receives the preamble part of theradio frame, the STA synchronizes, according to the L-STF in thepreamble part, with the AP associated with the STA, and performs channelestimation according to the L-LTF of the preamble part; and the STAacquires, by means of coherent reception, information that is related toduration of the radio frame and carried in the L-SIG of the preamblepart of the radio frame.

The STA associated with the AP determines, according to configurationinformation, included in the control domain, of an uplink/downlink datadomain in the radio frame, an OFDMA (orthogonal frequency divisionmultiple access) modulation parameter used by the data domain, and radioresource allocation indication information for the STA associated withthe AP, a resource block corresponding to the STA in the downlink datadomain in the data domain and a transmission parameter used for sendingdata of the resource block (for example, in an MCS or MIMO manner), andreceives and demodulates, on the determined resource block, the wirelesslocal area network data sent by the AP.

The data domain is sent in an OFDMA manner.

Step 705: When the data domain of the radio frame includes an uplinkdata domain, the STA associated with the AP sends, in the uplink datadomain included in the data domain, according to the control domain ofthe radio frame, wireless local area network data to the AP.

A specific operation of the sending, by the STA associated with the AP,in the uplink data domain included in the data domain, according to thecontrol domain of the radio frame, wireless local area network data tothe AP may be: performing, by the STA associated with AP, modulation andcoding, according to the control domain of the radio frame, on wirelesslocal area network data that needs to be sent, and sending, on aresource block corresponding to the STA, coded wireless local areanetwork data to the AP.

A specific operation of the performing, by the STA associated with theAP, modulation and coding, according to the control domain of the radioframe, wireless local area network data that needs to be sent may bethat: performing, by the STA associated with AP, according to an OFDMmodulation parameter included in the control domain of the radio frame,configuration information, included in the control domain, of anuplink/downlink data domain in the radio frame, and radio resourceallocation indication information for the STA associated with the AP,modulation and coding on the wireless local area network data that needsto be sent, determining a corresponding resource block of the STA in theuplink data domain, and sending, on the determined resource block,wireless local area network data on which modulation and coding areperformed to the AP.

Further, before the reserved duration ends, if the AP wants to end thescheduling window, that is, the AP gives up the right to use the radiochannel, the AP may broadcast a giving up control frame, to state thatthe AP gives up the right to use the radio channel. In this case,another AP or STA may acquire, in a contention manner, the right to usethe radio channel.

In this embodiment, when a right to use a radio channel is acquired, anAP may construct a radio frame, where the radio frame includes apreamble part, a control domain, and a data domain. The AP may increasetransmit power of the preamble part, and broadcast the preamble part, sothat not only a STA associated with the AP receives the preamble part,but also a STA not associated with the AP and another AP may receive thepreamble part, and thereby the STA not associated with the AP and theanother AP no longer transmit wireless local area network data by usingthe radio channel, avoiding interference to transmission of wirelesslocal area network data between the AP and the STA associated with theAP when the STA not associated with the AP and the another AP transmitwireless local area network data, and achieving a relatively goodeffect. In addition, because the data domain of the radio frame mayinclude multiple uplink data domains and multiple downlink data domains,and each uplink data domain or downlink data domain includes multipleradio resource blocks, each STA has a corresponding radio resourceblock. The STA associated with the AP may send, on a radio resourceblock corresponding to the STA in an uplink data domain, wireless localarea network data to the AP. The AP may send, on a radio resource blockcorresponding to a STA in a downlink data domain, wireless local areanetwork data to the STA associated with the AP. Because the AP may beassociated with multiple STAs, the wireless local area network data canbe transmitted between the AP and the STA in a one-to-many ormany-to-one relationship, improving spectrum utilization and network useefficiency.

Embodiment 6

FIG. 10 is an apparatus for transmitting wireless local area networkdata according to an embodiment. Referring to FIG. 10 , the apparatusincludes: a first transmitter 1001, a first receiver 1002, a firstmemory 1003, and a first processor 1004, which are configured to executethe following method for transmitting wireless local area network data,where:

the first processor 1004 is configured to construct a radio frame when aright to use a radio channel is acquired, where the radio frame includesat least a preamble part, a control domain, and a data domain, and thedata domain includes at least one downlink data domain;

the first transmitter 1001 is configured to send the preamble part andthe control domain to a station STA associated with the AP; and

the first transmitter 1001 is further configured to send, in a downlinkdata domain of the radio frame, wireless local area network data to theSTA associated with the AP.

Both the preamble part and the control domain are sent in an orthogonalfrequency division multiplexing OFDM manner compatible with the existingInstitute of Electrical and Electronics Engineers IEEE 802.11 standard,and the data domain is sent in an orthogonal frequency division multipleaccess OFDMA manner.

The preamble part is a preamble part compatible with the existing IEEE802.11, and the preamble part includes a legacy-short training fieldL-STF, a legacy-long training field L-LTF, and a legacy-signaling fieldL-SIG, where the L-STF is used to synchronize the STA associated withthe AP with the AP, and the L-LTF is used to enable the STA associatedwith the AP to perform channel estimation, to acquire, by means ofcoherent reception, information that is related to duration of the radioframe and carried in the L-SIG.

Optionally, a length LENGTH data domain in the L-SIG domain carries avalue related to the duration of the radio frame, and the duration,corresponding to the value, of the radio frame is greater than or equalto actual duration of the radio frame.

Further, the first processor 1004 is further configured to increasetransmit power of the preamble part of the radio frame, so that a STAnot associated with the AP and another AP receive the preamble part ofthe radio frame, and within reserved duration, the STA not associatedwith the AP and the another AP no longer transmit wireless local areanetwork data by using the radio channel, where the reserved duration isduration within which the AP owns the right to use the radio channel.

The control domain includes: configuration information of anuplink/downlink data domain in the radio frame, an OFDMA modulationparameter used by the data domain, and radio resource allocationindication information for the STA associated with the AP.

The configuration information of the uplink/downlink data domainincludes: a quantity of uplink data domains, a quantity of downlink datadomains, and transformation information between the uplink data domainand the downlink data domain.

Further, the OFDMA modulation parameter used by the data domainincludes: channel bandwidth of a system, a used cyclic prefix CP length,a fast Fourier transformation FFT order, and a quantity of availablesubcarriers.

The radio resource allocation indication information for the STAassociated with the AP includes: a first radio resource indication,where the first radio resource indication is used to indicate a radioresource block corresponding to a second radio resource indication usedby each scheduled STA to transmit data, or the first radio resourceindication is used to indicate a radio resource block used by eachscheduled STA to transmit data.

Optionally, the first radio resource indication includes: a size and aposition of a radio resource block indicated by the first radio resourceindication, and a modulation and coding scheme and/or a multiple-inputmultiple-output MIMO transmission manner used on the radio resourceblock.

Optionally, the first receiver 1002 is further configured to: when thedata domain includes an uplink data domain, receive, in the uplink datadomain included in the data domain, according to the control domain,wireless local area network data sent by the STA associated with the AP.

In this embodiment, when a right to use a radio channel is acquired, anAP may construct a radio frame, where a data domain of the radio framemay include at least one downlink data domain, the downlink data domainincludes multiple radio resource blocks, and each STA has acorresponding radio resource block. The AP may send, on a radio resourceblock corresponding to a STA in the downlink data domain, wireless localarea network data to a STA associated with the AP. When the data domainof the radio frame includes an uplink data domain, the uplink datadomain also includes multiple radio resource blocks, and each STA has acorresponding radio resource block. The STA associated with the AP maysend, on a radio resource block corresponding to the STA, wireless localarea network data to the AP. Because the AP may be associated withmultiple STAs, the wireless local area network data can be transmittedbetween the AP and the STA in a one-to-many or many-to-one relationship,improving spectrum utilization and network use efficiency.

Embodiment 7

FIG. 11 is an apparatus for transmitting wireless local area networkdata according to an embodiment. Referring to FIG. 11 , the apparatusincludes: a second transmitter 1101, a second receiver 1102, a secondmemory 1103, and a second processor 1104, which are configured toexecute the following method for transmitting wireless local areanetwork data, where:

the second receiver 1102 is configured to receive a preamble part and acontrol domain of a radio frame that are sent by an access point APassociated with the STA; and

the second receiver 1102 is further configured to receive, in a downlinkdata domain included in a data domain of the radio frame, according tothe preamble part and the control domain, wireless local area networkdata sent by the AP associated with the STA, where the data domainincludes at least one downlink data domain.

The preamble part is a preamble part compatible with the existingInstitute of Electrical and Electronics Engineers IEEE 802.11, and thepreamble part includes a legacy-short training field L-STF, alegacy-long training field L-LTF, and a legacy-signaling field L-SIG;and

accordingly,

the second processor 1104 is configured to perform, according to theL-STF, synchronization with the AP associated with the STA;

the second processor 1104 is further configured to perform channelestimation according to the L-LTF; and

the second receiver 1102 is further configured to acquire, by means ofcoherent reception, information that is related to duration of the radioframe and carried in the L-SIG.

A length LENGTH data domain in the L-SIG domain carries a value relatedto the duration of the radio frame, and the duration, corresponding tothe value, of the radio frame is greater than or equal to actualduration of the radio frame.

Further, the control domain includes: configuration information of anuplink/downlink data domain in the radio frame, an OFDMA modulationparameter used by the data domain, and radio resource allocationindication information for the STA associated with the AP.

Optionally, the configuration information of the uplink/downlink datadomain includes: a quantity of uplink data domains, a quantity ofdownlink data domains, and transformation information between the uplinkdata domain and the downlink data domain.

The OFDMA modulation parameter used by the data domain includes: channelbandwidth of a system, a used cyclic prefix CP length, a fast Fouriertransformation FFT order, and a quantity of available subcarriers.

Optionally, the radio resource allocation indication information for theSTA associated with the AP includes: a first radio resource indication,where the first radio resource indication is used to indicate a radioresource block corresponding to a second radio resource indication usedby each scheduled STA to transmit data, or the first radio resourceindication is used to indicate a radio resource block used by eachscheduled STA to transmit data.

Further, the first radio resource indication includes: a size and aposition of a radio resource block indicated by the first radio resourceindication, and a modulation and coding scheme and/or a multiple-inputmultiple-output MIMO transmission manner used on the radio resourceblock.

Optionally,

the second transmitter 1101 is configured to: when the data domainincludes an uplink data domain, send, in the uplink data domain includedin the data domain, according to the control domain, wireless local areanetwork data to the AP associated with the STA.

In this embodiment, when a right to use a radio channel is acquired, anAP may construct a radio frame, where a data domain of the radio framemay include at least one downlink data domain, the downlink data domainincludes multiple radio resource blocks, and each STA has acorresponding radio resource block. The AP may send, on a radio resourceblock corresponding to a STA in the downlink data domain, wireless localarea network data to a STA associated with the AP. When the data domainof the radio frame includes an uplink data domain, the uplink datadomain also includes multiple radio resource blocks, and each STA has acorresponding radio resource block. The STA associated with the AP maysend, on a radio resource block corresponding to the STA, wireless localarea network data to the AP. Because the AP may be associated withmultiple STAs, the wireless local area network data can be transmittedbetween the AP and the STA in a one-to-many or many-to-one relationship,improving spectrum utilization and network use efficiency.

A person of ordinary skill in the art may understand that all or some ofthe steps of the embodiments may be implemented by hardware or a programinstructing related hardware. The program may be stored in acomputer-readable storage medium. The storage medium may include: aread-only memory, a magnetic disk, or an optical disc.

The foregoing descriptions are merely exemplary embodiments, but are notintended to limit the disclosure. Any modification, equivalentreplacement, and improvement made without departing from the spirit andprinciple shall fall within the protection scope of the presentdisclosure.

It should further be noted that in this specification, relational termssuch as first and second are only used to distinguish one entity oroperation from another, and do not necessarily require or imply that anyactual relationship or sequence exists between these entities oroperations. Moreover, the terms “include”, “comprise”, or their anyother variant is intended to cover a non-exclusive inclusion, so that aprocess, a method, an article, or a device that includes a list ofelements not only includes those elements but also includes otherelements that are not expressly listed, or further includes elementsinherent to such a process, method, article, or device. An elementpreceded by “includes a . . . ” does not, without more constraints,preclude the presence of additional identical elements in the process,method, article, or device that includes the element.

Based on the description of the foregoing implementation manners, aperson skilled in the art may clearly understand that the embodimentsdisclosed herein may be implemented by software in addition to necessaryuniversal hardware, where the universal hardware includes a universalintegrated circuit, a universal CPU, a universal memory, a universalcomponent, or the like, or may be implemented by dedicated hardware,including an application-specific integrated circuit, a dedicated CPU, adedicated memory, a dedicated component, or the like. Based on such anunderstanding, the technical solutions disclosed herein may beimplemented in a form of a software product. The computer softwareproduct is stored in a readable storage medium, for example, variousmedia that can store software program code, such as a USB flash drive, aremovable hard disk, a read-only memory (ROM), a random access memory(RAM), a magnetic disk, or an optical disc, and includes severalinstructions for instructing a computer device (which may be a personalcomputer, a server, a network device, or the like) to perform themethods described in the embodiments.

The foregoing description enables a person skilled in the art toimplement or use the disclosed embodiments. Various modifications to theembodiments are obvious to a person skilled in the art, and generalprinciples defined in this specification may be implemented in otherembodiments without departing from the spirit or scope of thedisclosure. Therefore, the present innovation will not be limited to theembodiments described in this specification but extends to the widestscope that complies with the principles and novelty provided in thisspecification.

The following describes some specific implementation manners by way ofexample only.

For details of a “reserved channel part” in a contention window shownabove in FIG. 8 , refer to FIG. 8 a . Specifically, before theconstructing, by an AP, a radio frame after obtaining through contentiona right to use a channel, the method further includes: sending, by theAP, an RTS (Request To Send), and receiving one or more CTSs (Clear ToSend) that one or more STAs associated with the AP reply with, where theone or more CTSs are used to indicate that a STA sending the CTS canreceive or send data, (a channel condition allows receiving and sendingof data). More specifically, when receiving the CTS, othercommunications nodes nearby do not use the channel to performcommunication. That is, the STA protects, by sending the CTS, thechannel from being used by the communications nodes nearby, to avoidcausing interference.

More specifically, a receiver address of the RTS sent by the AP may be agroup address, or may be an address of a specified STA, or may beaddresses of all STAs associated with the AP. For example, the receiveraddress is represented by a default address, for example, by all zeros.After a STA that performs reception as instructed by the AP (that is, aSTA indicated by the receiver address) receives the RTS, the STA replieswith a CTS after a period of time, for example, after duration of anSIFS. For example, for a group of STAs in the STAs associated with theAP, particular STAs specified by the AP or all STAs reply with a CTSseparately. Such replies may be sent by using a time division, codedivision, frequency division, or OFDMA technology, or may be superposedand sent on exactly a same resource.

As mentioned above, not only the AP may construct the radio frameaccording to a quantity of STAs associated with the AP, but also the APmay construct the radio frame according to a service between the AP andthe STA associated with the AP. Certainly, the AP may also construct theradio frame in another manner. Specifically, the AP may determine,according to a received CTS, what kind of radio frame is to beconstructed. For example, the AP determines, according to a quantity ofreceived CTSs, a quantity of STAs that can be scheduled, and furtherdetermines scheduling duration or a quantity of radio frames to bescheduled, and a quantity of downlink subframes and a quantity of uplinksubframes in a radio frame or a ratio of downlink subframes to uplinksubframes in a radio frame. Further, if the STAs reply with the CTS in agroup manner, the AP may further determine whether MU-MIMO transmissionmay be used in a radio frame, and determine how many resources may beallocated to perform MU-MIMO transmission, so as to determine aninternal structure of the radio frame. For another example, the APdetermines a transmission MCS in a scheduling period according to signalstrength of the received CTS, so as to determine scheduling duration ora quantity of radio frames to be scheduled.

In frame structures shown in FIG. 8 , FIG. 8 a , and FIG. 9 , there maybe multiple specific frame structure replacing manners. For example, inthe disclosed embodiments, a radio frame includes in sequence: apreamble part compatible with the existing IEEE 802.11 (hereinafterbriefly referred to as Legacy preamble), a preamble part used in anext-generation standard (for example, HEW preamble), and the firstdownlink subframe, or may include another downlink subframe or an uplinksubframe. The another downlink subframe or uplink subframe includes atraining sequence field part of the next-generation standard, such asHEW STF and HEW LTF parts, and data, and does not include the preamblepart compatible with the existing IEEE 802.11.

In various frame structures provided by the disclosed embodiments, aradio frame includes: one or more downlink subframes and one or moreuplink subframes. In this way, on the basis of the frame structurementioned in the previous paragraph, a downlink subframe and an uplinksubframe are alternated, the first subframe after the alternationincludes a Legacy preamble and a preamble used in a next-generationstandard (for example, HEW preamble). For example, after the TTGmentioned above, and before the first uplink data, the first subframeincludes a Legacy preamble and a preamble used in a next-generationstandard (for example, HEW preamble). Remaining non-first downlinksubframes and non-first uplink subframes include a training sequencefield part of the next-generation standard, for example, HEW STF and HEWLTF parts, and do not include the Legacy preamble and another part inthe preamble of the next-generation standard.

In various frame structures provided by this implementation manner, aradio frame includes ACK information for a downlink subframe of theradio frame. For example, in a radio frame, ACK information for adownlink subframe is carried in a subsequent uplink subframe after thedownlink subframe. These uplink subframes may be default. For example,the first uplink subframe or the first several uplink subframes afterthe downlink subframe carry the ACK information for the downlinksubframe. In an example, the first UL subframe is used as an ACK reply,and the second and third UL subframes are used for transmission ofuplink data payload. Certainly, these uplink subframes may also beindicated to an uplink STA by the AP in advance.

In a more specific example, after the uplink subframe that carries theACK information for the downlink subframe, a radio frame includes adownlink subframe, where the downlink subframe is used to triggertransmission of a subsequent uplink subframe that carries data(payload), and the downlink subframe may carry information such as aresource allocation indicator, for example, resource block informationof the subsequent uplink subframe. The downlink subframe may includeonly a legacy preamble and a preamble of a next-generation standard, forexample, an HEW preamble, or may include a MAC PDU part besides theforegoing two parts.

It is also mentioned in the foregoing implementation manners that, theconfiguration information of the uplink/downlink data domain mayinclude: a quantity of uplink data domains, a quantity of downlink datadomains, and transformation information between the uplink data domainand the downlink data domain. It should be noted that, the configurationinformation of the uplink/downlink data domain may have multiplespecific forms, which are not limited in the implementation manners ofthe disclosed embodiments.

For example, referring to a schematic diagram of a data structure inFIG. 8 b , in an implementation manner, Length in an L-SIG of a PPDU,that is, L-Length, is used to indicate a sum of lengths of an uplinkdata domain and a downlink data domain (downlink subframe and uplinksubframe), and an HE-SIG includes information indicating a length of adownlink subframe (which, for example, may be named HE-Length). Withthis structure, downlink transmission and uplink transmission are fullyprotected.

For a WLAN system using the foregoing data structure, a receive endperforms the following processing after receiving a PPDU:

Step 1: Read an L-Length carried in an L-SIG of the PPDU, to obtain asum of lengths of a current downlink subframe (that is, the currentPPDU) and an uplink subframe (uplink PPDU).

Step 2: After it is learned that a current frame is a frame of an HEtype, learn a length of the current downlink subframe (that is, thecurrent PPDU) according to length information HE-Length carried in anHE-SIG.

Step 3: Further, obtain a length of an uplink subframe (such as an UL MUPPDU) according to the L-Length and the HE-Length. Specifically, Lengthof the uplink subframe=L-Length−HE-Length−SIFS.

In a more specific example, for a receive end (HE receive end) using theforegoing data structure, if only downlink data needs to be received,signal receiving or CCA detection may be stopped within a time of thelength of the uplink subframe obtained in step 3. In this way,obviously, power can be reduced to some extent. If the receive end needsto send uplink data, the length of the uplink subframe obtained in step3 is a limit or threshold for the receive end to send uplink data, thatis, a length of data sent by the receive end needs to be less than thecalculated length of the uplink subframe (UL MU PPDU).

After receiving the PPDU, another receive end (non-HE receive end) readsthe L-Length carried in the L-SIG of the PPDU, and uses the L-Length asa length of the current frame (PPDU). Within a time indicated by thelength, the non-HE receive end does not actively send data, to avoidcausing interference to current transmission, or may no longer receive asignal or may stop CCA detection. In this way, obviously, power can alsobe reduced to some extent.

Further, length units of the L-length, the HE-Length, and the SIFS areunified or consistent, and are, for example, time, a quantity of bits,or a quantity of OFDM/OFDMA symbols.

For example, one method is to use time, for example, microsecond (μs),as the unit. Specifically, the L-length indicates a sum of time lengthsof a downlink PPDU, an uplink PPDU, and an inter-frame space; theHE-Length indicates a time length of a downlink PPDU. Another method isto use an existing unit of the L-Length, that is, byte, as the unit.

In a specific example, a specific calculation method includes:T _(L-Length) =T _(DL_PPDU) +T _(UL_PPDU)+SIFS+T _(HE-SIG)T _(HE-Length) =T _(DL_PPDU) +T _(HE-SIG)

L-Length=ceiling[T_(L-Length)/T_(symbol)]*N_(symbol), where a unit ofN_(symbol) is byte, which refers to a quantity of bytes included in eachsymbol; andHE-Length=ceiling[T _(HE-Length) /T _(symbol) ]*N _(symbol)

If a quantity of OFDM/OFDMA symbols is used as a unit of length,L-Length=ceiling[T _(L-Length) /T _(symbol)] andHE-Length=ceiling[T _(HE-Length) /T _(symbol)]

In the foregoing formulas, TL-Length is a time length indicated by theL-Length, T_(DL_PPDU) is a time length required for sending a DL PPDU,T_(UL_PPDU) is a time length required for sending an UL PPDU, SIFS is ashort inter-frame space, T_(HE-Length) is a time length indicated by theHE-Length, T_(HE-SIG) is a time length required for sending an HE-SIG,T_(symbol) is a time length required for sending an OFDM symbol, andCeiling[x] is a round-up operation performed on x.

In addition, refer to FIG. 8 c , which is a schematic structural diagramof an uplink subframe sent by a STA. An L-Length in an L-SIG of theuplink subframe (uplink PPDU) is used to indicate a length of amulti-user part (uplink MU PPDU, including an HE-SIG and an uplink MUPart) of the uplink subframe. In this way, uplink transmission can bebetter protected.

In a specific example, in the uplink PPDU, by using a length unit beingμs as an example, T_(L-Length)=T_(UL_PPDU)−20, where 20 is a length of alegacy preamble.

Further, the uplink subframe sent by the STA may further include uplinkresource allocation information (Resource Allocation) sent by an AP, andspecifically, the uplink resource allocation information may be includedin the HE-SIG of the sent uplink subframe.

On the basis of the foregoing data structure, after receiving the uplinksubframe, a non-destination HE STA may perform the following processing:

Step 1: Read an L-Length to learn duration of the current frame.

Step 2: Continue to read an HE-SIG to learn uplink resource allocationinformation, and read Duration in a MAC header in a resource blockaccording to the uplink resource allocation information.

Step 3: The non-destination HE STA can learn current transmitopportunity (TXOP) duration and effectively set a NAV according to theDuration information.

Duration indicates a time length of a current TXOP; therefore, itslength is not limited to the current frame.

For the uplink subframe, the uplink subframe can be better protected byusing the L-Length and/or Duration in the HE-SIG.

If the STA needs to distinguish whether a current frame is an uplinksubframe or a downlink subframe, a distinguishing method is to comparelengths of the L-Length and the HE-Length. For example, if the two areequal or approximate, it is determined that the current frame is anuplink subframe; and if the two are not equal or differ significantly,it is determined that the current frame is a downlink subframe.

What is claimed is:
 1. An apparatus for transmitting wireless local areanetwork (WLAN) data, the apparatus comprising: a non-transitory memorycomprising processor-executable instructions; and one or more processorsin communication with the memory, wherein the one or more processors areconfigured to execute the processor-executable instructions tofacilitate: within a scheduling window, sending a downlink (DL) part,wherein the DL part includes a first preamble, a second preamble, and aDL multi-user (MU) part, wherein the DL part is configured to triggertransmission of an uplink (UL) part; and within the scheduling window,after sending the DL part, receiving the UL part, wherein the UL partincludes a third preamble, a fourth preamble and an UL MU part; whereinthe UL MU part includes: ACK information for the DL part; and UL data;wherein a media access control (MAC) header of the UL part includes aduration which indicates a time length of a current transmit opportunity(TXOP) for a non-destination station (STA) setting a network allocationvector (NAV) and protecting the UL part, and wherein the current TXOP iswithin the scheduling window.
 2. The apparatus according to claim 1,wherein the UL part comprises multiple UL subframes, wherein themultiple UL subframes comprise a UL subframe carrying the ACKinformation and another UL subframe for sending the UL data.
 3. Theapparatus according to claim 1, wherein a first DL subframe sent withinthe scheduling window includes: the first preamble, the second preambleand a DL MU subframe, and wherein a first UL subframe received withinthe scheduling window includes: the third preamble, the fourth preambleand an UL MU subframe.
 4. The apparatus according to claim 3, wherein anon-first UL subframe or a non-first DL subframe includes a trainingsequence compatible with a next-generation standard, does not includethe first preamble, and does not include other subframes of the secondpreamble except the training sequence compatible with thenext-generation standard.
 5. The apparatus according to claim 1, whereinthe first preamble of the DL part and the third preamble of the UL partcomprise a legacy-short training field (L-STF), a legacy-long trainingfield (L-LTF), and a legacy-signaling field (L-SIG); and wherein thesecond preamble of the DL part and the fourth preamble of the UL partcorrespond to a next-generation standard.
 6. The apparatus according toclaim 1, wherein a DL subframe of the DL part carries information of aresource allocation indicator of a subsequent UL subframe of the ULpart; and wherein each DL subframe of the DL part sent within thescheduling window includes data to multiple stations (STAs) inrespective radio resource blocks, and wherein each UL subframe of the ULpart received within the scheduling window includes data of multipleSTAs in respective resource blocks indicated by the information of theresource allocation indicator to be sent to the apparatus.
 7. Anapparatus for transmitting wireless local area network (WLAN) data, theapparatus comprising: a non-transitory memory comprisingprocessor-executable instructions; and one or more processors incommunication with the memory, wherein the one or more processors areconfigured to execute the processor-executable instructions tofacilitate: within a scheduling window, receiving a downlink (DL) part,wherein the DL part includes a first preamble, a second preamble, and aDL multi-user (MU) part, and wherein the DL part triggers transmissionof an uplink (UL) part; and within the scheduling window, afterreceiving the DL part, sending the UL part triggered by the DL part,wherein the UL part includes a third preamble, a fourth preamble and anUL MU part; wherein the UL MU part includes: ACK information for the DLpart; and UL data; wherein a media access control (MAC) header of the ULpart includes a duration which indicates a time length of a currenttransmit opportunity (TXOP) for a non-destination station (STA) settinga network allocation vector (NAV) and protecting the UL part, andwherein the current TXOP is within the scheduling window.
 8. Theapparatus according to claim 7, wherein the UL part comprises multipleUL subframes, wherein the multiple UL subframes comprise a UL subframecarrying the ACK information and another UL subframe for sending the ULdata.
 9. The apparatus according to claim 7, wherein a first DL subframereceived within the scheduling window includes: the first preamble, thesecond preamble and a DL MU subframe, and wherein a first UL subframesent within the scheduling window includes: the third preamble, thefourth preamble and an UL MU subframe.
 10. The apparatus according toclaim 9, wherein a non-first UL subframe or a non-first DL subframeincludes a training sequence compatible with a next-generation standard,does not include the first preamble, and does not include othersubframes of the second preamble except the training sequence compatiblewith the next-generation standard.
 11. The apparatus according to claim7, wherein the first preamble of the DL part and the third preamble ofthe UL part comprise a legacy-short training field (L-STF), alegacy-long training field (L-LTF), and a legacy-signaling field(L-SIG); and wherein the second preamble of the DL part and the fourthpreamble of the UL part correspond to a next-generation standard. 12.The apparatus according to claim 7, wherein a DL subframe of the DL partcarries information of a resource allocation indicator for a subsequentUL subframe of the UL part; and wherein each DL subframe of the DL partreceived within the scheduling window includes data to multiple stations(STAs) in respective radio resource blocks, and wherein each UL subframeof the UL part sent within the scheduling window includes data ofmultiple STAs in respective resource blocks indicated by the informationof the resource allocation indicator.
 13. A method for transmittingwireless local area network (WLAN) data, wherein the method comprises:within a scheduling window, sending, by an access point, a downlink (DL)part, wherein the DL part includes a first preamble, a second preamble,and a DL multi-user (MU) part, and wherein the DL part is configured totrigger transmission of an uplink (UL) part; and within the schedulingwindow, after sending the DL part, receiving, by the access point, theUL part, wherein the UL part includes a third preamble, a fourthpreamble and an UL MU part; wherein the UL MU part includes: ACKinformation for the DL part; and UL data; wherein a DL subframe of theDL part carries information of a resource allocation indicator for asubsequent UL subframe of the UL part; and wherein a media accesscontrol (MAC) header of the UL part includes a duration which indicatesa time length of a current transmit opportunity (TXOP) for anon-destination station (STA) setting a network allocation vector (NAV)and protecting the UL part, and wherein the current TXOP is within thescheduling window.
 14. The method according to claim 13, wherein the ULpart comprises multiple UL subframes, wherein the multiple UL subframescomprise a UL subframe carrying the ACK information and another ULsubframe for sending the UL data.
 15. The method according to claim 13,wherein a first DL subframe sent within the scheduling window includes:the first preamble, a second preamble and a DL MU subframe, and whereina first UL subframe received within the scheduling window includes: thethird preamble, the fourth preamble and an UL MU subframe.
 16. Themethod according to claim 13, wherein each DL subframe of the DL partsent within the scheduling window includes data to multiple stations(STAs) in respective radio resource blocks, and wherein each UL subframeof the UL part received within the scheduling window includes data ofmultiple STAs in respective resource blocks indicated by the informationof the resource allocation indicator to be sent to the access point. 17.A method for transmitting wireless local area network (WLAN) data, on astation side, wherein the method comprises: within a scheduling window,receiving, by a station, a downlink (DL) part, wherein the DL partincludes a first preamble, a second preamble, and a DL multi-user (MU)part, and wherein the DL part triggers transmission of an uplink (UL)part; and within the scheduling window, after receiving the DL part,sending, by the station, the UL part triggered by the DL part, whereinthe UL part includes a third preamble, a fourth preamble and an UL MUpart; wherein the UL MU part includes: ACK information for the DL part;and UL data; wherein a media access control (MAC) header of the UL partincludes a duration which indicates a time length of a current transmitopportunity (TXOP) for a non-destination station setting a networkallocation vector (NAV) and protecting the UL part, and wherein thecurrent TXOP is within the scheduling window.
 18. The method accordingto claim 17, wherein the UL part comprises multiple UL subframes,wherein the multiple UL subframes comprise a UL subframe carrying theACK information and another UL subframe for sending the UL data.
 19. Themethod according to claim 17, wherein a first DL subframe receivedwithin the scheduling window includes: the first preamble, the secondpreamble and a DL MU subframe, and wherein a first UL subframe sentwithin the scheduling window includes: the third preamble, the fourthpreamble and an UL MU subframe.
 20. The method according to claim 17,wherein a DL subframe of the DL part carries information of a resourceallocation indicator for a subsequent UL subframe of the UL part; andwherein each DL subframe of the DL part received within the schedulingwindow includes data to multiple stations in respective radio resourceblocks, and wherein each UL subframe of the UL part sent within thescheduling window includes data of multiple stations in respectiveresource blocks indicated by the information of the resource allocationindicator.